drivers/gpu/drm/panfrost/panfrost_devfreq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright 2019 Collabora ltd. */
   3
   4 #include <linux/clk.h>
   5 #include <linux/devfreq.h>
   6 #include <linux/devfreq_cooling.h>
   7 #include <linux/nvmem-consumer.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/pm_opp.h>
  10
  11 #include "panfrost_device.h"
  12 #include "panfrost_devfreq.h"
  13
  14 static void panfrost_devfreq_update_utilization(struct panfrost_devfreq *pfdevfreq)
  15 {
  16         ktime_t now, last;
  17
  18         now = ktime_get();
  19         last = pfdevfreq->time_last_update;
  20
  21         if (pfdevfreq->busy_count > 0)
  22                 pfdevfreq->busy_time += ktime_sub(now, last);
  23         else
  24                 pfdevfreq->idle_time += ktime_sub(now, last);
  25
  26         pfdevfreq->time_last_update = now;
  27 }
  28
  29 static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
  30                                    u32 flags)
  31 {
  32         struct panfrost_device *ptdev = dev_get_drvdata(dev);
  33         struct dev_pm_opp *opp;
  34         int err;
  35
  36         opp = devfreq_recommended_opp(dev, freq, flags);
  37         if (IS_ERR(opp))
  38                 return PTR_ERR(opp);
  39         dev_pm_opp_put(opp);
  40
  41         err =  dev_pm_opp_set_rate(dev, *freq);
  42         if (!err)
  43                 ptdev->pfdevfreq.current_frequency = *freq;
  44
  45         return err;
  46 }
  47
  48 static void panfrost_devfreq_reset(struct panfrost_devfreq *pfdevfreq)
  49 {
  50         pfdevfreq->busy_time = 0;
  51         pfdevfreq->idle_time = 0;
  52         pfdevfreq->time_last_update = ktime_get();
  53 }
  54
  55 static int panfrost_devfreq_get_dev_status(struct device *dev,
  56                                            struct devfreq_dev_status *status)
  57 {
  58         struct panfrost_device *pfdev = dev_get_drvdata(dev);
  59         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
  60         unsigned long irqflags;
  61
  62         status->current_frequency = clk_get_rate(pfdev->clock);
  63
  64         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
  65
  66         panfrost_devfreq_update_utilization(pfdevfreq);
  67
  68         status->total_time = ktime_to_ns(ktime_add(pfdevfreq->busy_time,
  69                                                    pfdevfreq->idle_time));
  70
  71         status->busy_time = ktime_to_ns(pfdevfreq->busy_time);
  72
  73         panfrost_devfreq_reset(pfdevfreq);
  74
  75         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
  76
  77         dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
  78                 status->busy_time, status->total_time,
  79                 status->busy_time / (status->total_time / 100),
  80                 status->current_frequency / 1000 / 1000);
  81
  82         return 0;
  83 }
  84
  85 static struct devfreq_dev_profile panfrost_devfreq_profile = {
  86         .timer = DEVFREQ_TIMER_DELAYED,
  87         .polling_ms = 50, /* ~3 frames */
  88         .target = panfrost_devfreq_target,
  89         .get_dev_status = panfrost_devfreq_get_dev_status,
  90 };
  91
  92 static int panfrost_read_speedbin(struct device *dev)
  93 {
  94         u32 val;
  95         int ret;
  96
  97         ret = nvmem_cell_read_variable_le_u32(dev, "speed-bin", &val);
  98         if (ret) {
  99                 /*
 100                  * -ENOENT means that this platform doesn't support speedbins
 101                  * as it didn't declare any speed-bin nvmem: in this case, we
 102                  * keep going without it; any other error means that we are
 103                  * supposed to read the bin value, but we failed doing so.
 104                  */
 105                 if (ret != -ENOENT && ret != -EOPNOTSUPP) {
 106                         DRM_DEV_ERROR(dev, "Cannot read speed-bin (%d).", ret);
 107                         return ret;
 108                 }
 109
 110                 return 0;
 111         }
 112         DRM_DEV_DEBUG(dev, "Using speed-bin = 0x%x\n", val);
 113
 114         return devm_pm_opp_set_supported_hw(dev, &val, 1);
 115 }
 116
 117 int panfrost_devfreq_init(struct panfrost_device *pfdev)
 118 {
 119         int ret;
 120         struct dev_pm_opp *opp;
 121         unsigned long cur_freq;
 122         struct device *dev = &pfdev->pdev->dev;
 123         struct devfreq *devfreq;
 124         struct thermal_cooling_device *cooling;
 125         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 126         unsigned long freq = ULONG_MAX;
 127
 128         if (pfdev->comp->num_supplies > 1) {
 129                 /*
 130                  * GPUs with more than 1 supply require platform-specific handling:
 131                  * continue without devfreq
 132                  */
 133                 DRM_DEV_INFO(dev, "More than 1 supply is not supported yet\n");
 134                 return 0;
 135         }
 136
 137         ret = panfrost_read_speedbin(dev);
 138         if (ret)
 139                 return ret;
 140
 141         ret = devm_pm_opp_set_regulators(dev, pfdev->comp->supply_names);
 142         if (ret) {
 143                 /* Continue if the optional regulator is missing */
 144                 if (ret != -ENODEV) {
 145                         if (ret != -EPROBE_DEFER)
 146                                 DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
 147                         return ret;
 148                 }
 149         }
 150
 151         ret = devm_pm_opp_of_add_table(dev);
 152         if (ret) {
 153                 /* Optional, continue without devfreq */
 154                 if (ret == -ENODEV)
 155                         ret = 0;
 156                 return ret;
 157         }
 158         pfdevfreq->opp_of_table_added = true;
 159
 160         spin_lock_init(&pfdevfreq->lock);
 161
 162         panfrost_devfreq_reset(pfdevfreq);
 163
 164         cur_freq = clk_get_rate(pfdev->clock);
 165
 166         opp = devfreq_recommended_opp(dev, &cur_freq, 0);
 167         if (IS_ERR(opp))
 168                 return PTR_ERR(opp);
 169
 170         panfrost_devfreq_profile.initial_freq = cur_freq;
 171
 172         /*
 173          * We could wait until panfrost_devfreq_target() to set this value, but
 174          * since the simple_ondemand governor works asynchronously, there's a
 175          * chance by the time someone opens the device's fdinfo file, current
 176          * frequency hasn't been updated yet, so let's just do an early set.
 177          */
 178         pfdevfreq->current_frequency = cur_freq;
 179
 180         /*
 181          * Set the recommend OPP this will enable and configure the regulator
 182          * if any and will avoid a switch off by regulator_late_cleanup()
 183          */
 184         ret = dev_pm_opp_set_opp(dev, opp);
 185         if (ret) {
 186                 DRM_DEV_ERROR(dev, "Couldn't set recommended OPP\n");
 187                 return ret;
 188         }
 189
 190         /* Find the fastest defined rate  */
 191         opp = dev_pm_opp_find_freq_floor(dev, &freq);
 192         if (IS_ERR(opp))
 193                 return PTR_ERR(opp);
 194         pfdevfreq->fast_rate = freq;
 195
 196         dev_pm_opp_put(opp);
 197
 198         /*
 199          * Setup default thresholds for the simple_ondemand governor.
 200          * The values are chosen based on experiments.
 201          */
 202         pfdevfreq->gov_data.upthreshold = 45;
 203         pfdevfreq->gov_data.downdifferential = 5;
 204
 205         devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
 206                                           DEVFREQ_GOV_SIMPLE_ONDEMAND,
 207                                           &pfdevfreq->gov_data);
 208         if (IS_ERR(devfreq)) {
 209                 DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
 210                 return PTR_ERR(devfreq);
 211         }
 212         pfdevfreq->devfreq = devfreq;
 213
 214         cooling = devfreq_cooling_em_register(devfreq, NULL);
 215         if (IS_ERR(cooling))
 216                 DRM_DEV_INFO(dev, "Failed to register cooling device\n");
 217         else
 218                 pfdevfreq->cooling = cooling;
 219
 220         return 0;
 221 }
 222
 223 void panfrost_devfreq_fini(struct panfrost_device *pfdev)
 224 {
 225         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 226
 227         if (pfdevfreq->cooling) {
 228                 devfreq_cooling_unregister(pfdevfreq->cooling);
 229                 pfdevfreq->cooling = NULL;
 230         }
 231 }
 232
 233 void panfrost_devfreq_resume(struct panfrost_device *pfdev)
 234 {
 235         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 236
 237         if (!pfdevfreq->devfreq)
 238                 return;
 239
 240         panfrost_devfreq_reset(pfdevfreq);
 241
 242         devfreq_resume_device(pfdevfreq->devfreq);
 243 }
 244
 245 void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
 246 {
 247         struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
 248
 249         if (!pfdevfreq->devfreq)
 250                 return;
 251
 252         devfreq_suspend_device(pfdevfreq->devfreq);
 253 }
 254
 255 void panfrost_devfreq_record_busy(struct panfrost_devfreq *pfdevfreq)
 256 {
 257         unsigned long irqflags;
 258
 259         if (!pfdevfreq->devfreq)
 260                 return;
 261
 262         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
 263
 264         panfrost_devfreq_update_utilization(pfdevfreq);
 265
 266         pfdevfreq->busy_count++;
 267
 268         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
 269 }
 270
 271 void panfrost_devfreq_record_idle(struct panfrost_devfreq *pfdevfreq)
 272 {
 273         unsigned long irqflags;
 274
 275         if (!pfdevfreq->devfreq)
 276                 return;
 277
 278         spin_lock_irqsave(&pfdevfreq->lock, irqflags);
 279
 280         panfrost_devfreq_update_utilization(pfdevfreq);
 281
 282         WARN_ON(--pfdevfreq->busy_count < 0);
 283
 284         spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
 285 }